This is the second in a series of posts that came out of the “Brewing 101” presentation we made at the Mad River Taste Place a year ago. To review, the brewing variables we are covering are:
The Grind
The Ratio
The Water
The Method
The Filter
With that, let’s get to it!
The Ratio
In the simplest sense, brewed coffee is a mix of ground, roasted beans and water. We’ll be referring to this as the coffee:water ratio, which is basically #parts of coffee mixed with #parts water. For example, a 1:17 ratio would be 1 part coffee to 17 parts water. This is most easily parsed out by using a gram scale to weigh out your coffee and water. Weighing your coffee and water is highly recommended as it yields more consistent brews then volume measurements.
Real life example: Let’s say we want to make a pourover for two people. Using a 1:16 brew ratio, we would use 30 grams of ground coffee and 480 grams of water (480/30=16). Knowing some of the water used will stay in the coffee bed after brewing, our final beverage brewed will end up being less than the amount of water we added. We usually find we lose around 60 grams of water to the coffee bed in the above scenario, so the result is two mugs of approximately 210g (~7 fluid ounces). If more final beverage is desired, the amount of water, and therefore ground coffee would increase, but maintaining the 1:16 ratio.
Water pulls what we call soluble material out of the ground coffee. No matter what path these two ingredients take, whether that’s through the portafilter of an espresso machine at 9 times atmospheric pressure or just hanging out in a french press for four minutes, coffee is made when water and ground beans come together. The proportion of coffee to water can result in a beverage that is anywhere from thin, weak and sour, to strong, heavy and bitter. The Specialty Coffee Association conducted a series of experiments back in the 1950’s and found that there is an ideal range for the water-to-coffee ratio. (Please keep in mind that these are guidelines set using subjective tasting data from a particular set of people in a particular time. Again, sensory is subjective, and preferences can vary widely by societal trends, cultural differences, location, etc. and there is no right or wrong. If it tastes good, drink it that way.) The chart below summarizes their findings. The X axis represents the proportion of extracted soluble coffee material to water in the beverage (“concentration”). The Y axis represents the percentage of all the coffee that was successfully extracted from the grounds (“yield”)
You’ll note that this chart isn’t immediately useful to answer the question “what ratio should I use?” That’s because of the other variables. If you’re making a pot from your auto-drip machine, the ratio is different than if you’re making a carafe of french press coffee. As explained in our first post, these methods use different grind sizes. The amount of yield from a finer ground coffee for an auto-drip is higher on a weight basis than the yield from a coarser ground coffee used in a french press. This is due to the increased surface area of a finer grind. The first post goes into great depth on how grind size impacts your cup, but for this post, the takeaway from this chart is that there is a sweet spot to aim for that avoids the extremes of weak/strong, sour/bitter. The ratios we provide below are what we’ve found works for us. Adjust as you see fit.
So, what ratio should you use? Different brewing methods yield their best results using different ratios. Generally speaking, the finer the grind, the less coffee is used per unit of water. There are definite exceptions, espresso being the most obvious. That’s why you usually see more coffee used in french press or cold brew recipes than a pour over or aeropress recipe. The infographic below illustrates how the ratio changes with brewing technique, grind size, and time of extraction.
As with everything in coffee, though, these are just starting points. For example, you can find literally dozens of different brewing techniques for the Aeropress, all with their own unique brew ratio and grind size. But most importantly, good coffee is just like good jazz: if it tastes good, it is good.